edge of the clamp cuts itself into the tissue of the host and acts as a vise, 

 cutting out the tissue in such a fashion that it occupies a considerably 

 greater space inside the clamp than at the place where the clamp adjoins 

 the body. If one cuts the entire tissue which was drawn into the cavity 

 of the clamp he will see a more or less ovally outlined area. In addition, 

 to that, the part of these tissues drawn into the clamp is divided into 

 four parts corresponding to the four sections formed by the chitinous 

 elements. With this it is fully understandable that the imprints of the two 

 anterior sections, i.e. , those fixed by the anterior valve of the clamp, 

 appear as being cut out the most. On the cross-sections through the drawn 

 tissues we can observe that each sector has the appearance of a regularly 

 convex papilla which indicates the presence of suction and not just a 

 mechanical grasping during pinching. 



From w^hat has been said before, one can conclude that the 

 presence of either pinching action of the clamps or of a simultaneous 

 pinching -sucking one is characteristic; for all Diclidophoridae. With this 

 the significance of either method increases not so much from the peculi- 

 arities of the structure of the clamp but from the substratum to which the 

 attachment takes place. In other words, the clamps on the gill filaments 

 bascially act as clamps, whereas on the surfaces of the cavities of the 

 gills and of the mouth the sucking function sharply increases. Hence, the 

 division into two subfamilies according to the present characteristic will 

 hardly bear criticism and is not taken into consideration by us even though 

 it be tempting, for the genus Diclidophora parasitizes gadoids, whereas 

 Choricotyle--the Perciformes. 



The interrelationships of the genera are not quite clear, un- 

 doubtedly the genus Diclidophora is more specialized and morphologically 

 complex, whereas Diclidophoropsis is closer to the initial ancestral forms, 

 which is substantiated not only by the structure of the attaching apparatus 

 but also by the presence of two vaginal apertures. The genus Choricotyle 

 occupies a position closer to Diclidophora than to Diclidophorops is. This 

 also pertains to the genus Heterobothriunn. On the other hand, it is probable that 

 Cyclobothrium is more primitive than the last genus and is closer to 

 Diclidophoropsis. Pedocotyle stands somewhat apart. Apparently this 

 genus represents a deviation from the general type of development. In a 

 certain measure its structure is interesting from the point of view of con- 

 vergency with Hexabothriidae. Because of some analogous peculiarities in 

 the nature of attachment, one can think that here takes place a lack of develop- 

 ment of the first pair of clamps. Finally the characteristics of the genus 

 Echinopelma cause considerable perplexity. It is undoubtedly close to p. 438 



Choricotyle but the presence of a single vaginal duct differentiates it from 

 this genus if one considers that Choricotyle does not have a vaginal duct 

 as is commonly accepted. However, one must think that this is possibly 

 incorrect even though in all re'sume's it is written that Diclidophora does 

 not have a vagina (Price, 1943a, Sproston, 1946, and others). Despite 



524 



