半滑舌鳎侧线器官和无眼侧皮肤表面的特殊结构

为了解决半滑舌鳎的摄食难题,探讨其摄食机理,本文采用光镜和扫描电镜手段对半滑舌鳎有眼侧侧线管和无眼侧皮肤表面的特殊结构进行了研究。结果表明(1)有眼侧:半滑舌鳎侧线孔圆形,孔径与所在部位侧线管径相同,孔上并连有一胶质管,这种特殊结构既可以提高管道内感觉器官(管道神经丘)的敏感性,又可阻止外界异物进入侧线管内部,具有保护作用;半滑舌鳎口腔附近的侧线管管径及侧线孔孔径较其它部位大,侧线孔密度高,认为口腔附近侧线管道内的感觉器官(管道神经丘)的敏感性较其它部位高,在鱼类捕食行为中具有重要作用;(2)无眼侧:躯干部表面覆盖圆鳞,头部皮肤无鳞,表面被覆相互连结的黏液管,形成黏液管皮肤;极其发达的黏液管构成管状黏液分泌系统。扫描电镜观察发现,在头部黏液管皮肤表面镶嵌着一种乳头状突起(Pailla),其典型特征是在表面被覆一盾牌状结构,一般多个簇生在一起,很少单独存在,其分布密度是从吻端向内逐渐减少,组织切片显示内部结构周边是套细胞,中央是感觉细胞,具一柄或两柄。根据其外部形态和内部结构,作者推测,这可能是半滑舌鳎特有的一种触觉器官,并在其摄食行为中起重要作用。半滑舌鳎极其发达的黏液分泌系统对于裸露的乳头状突起(Pailla)具有相当重要的保护作用。

Lateral-line sense organs and dermal surface structures of the tongue sole Cynoglossus semilaevis

The lateral-line sense organs and unusual dermal surface structure on the abocular side of C.semilaevis were examined using light and scanning electron microscopic techniques. Results showed that (1) on the ocular side: the canal pores of C.semilaevis are round; the diameter of canal pore is exactly equal to that of the lateral-line canal at the same place. Every canal pore connects with one colloid canal which extends into the lateral-line canal. This unusual structure may not only improve the sensitivity of canal organs (canal neuromasts), but may protect the lateral-line canal from penetrating particles. The widest diameter of the canal pores and lateral-line canal, as well as the highest densities of canal pores, occur around the mouth of C.semilaevis. These characteristics may play an important role in feeding behavior. (2) On the abocular side,the skin of the trunk is covered with cycloid scales. However, the epidermal surface of the head is quite astonishing; here, scales are nonexistent,and the head is covered with a conjoint mucus tube. As a result, a tubular mucus secretion system is produced. Scanning electron microscopy revealed the presence of unusual papillae on the abocular side of the head. Their most surprising feature is that a shield-shaped mantle with flanges is wrapped across the top of each papilla, generally these organs occur in groups, hardly single, they extend from the tip of the head to just inside the scaly region and sometimes to the rear section of the operculum.Examination of the interior structures revealed the presence of mantle-cells at the periphery and hair-cells centrally. In addition, they possessed one or two handles along the long-axis of the interior structure. Based upon their shape and internal structure, we suggest that these papillae may be touch receptors which play some role in the feeding behavior of C.semilaevis. The highly developed mucus secretion system of C.semilaevis may be important in protecting these exposed papilla.