84 MR W. TURNER AND DR H. S. WILSON ON THE 



animal alive for three weeks. If, in the act of separation, the bar be removed 

 from the claspers, death takes place at an earlier period. 



Male. — We have not succeeded in finding the male of this species. Following 

 the rule pursued by these parasites, we had expected to have seen it attached to 

 the body of the female, but we have carefully searched the different specimens we 

 have obtained without meeting with it. Retzius makes no mention of the male. 

 Kroyer thinks that he found on one of his specimens a male attached at the 

 anus. He describes a creature " about one-third of a line long, with somewhat 

 of a crustacean form, with two 2- jointed antennae, a 3-jointed thoracic portion, a 

 curved tail, and two strong hooked feet. The head appeared to present the trace 

 of an eye. He can say nothing further about it." 



Larva. — Neither Retzius nor Kroyer have given any description of the larva. 

 In two of our specimens the ova were in such a stage of development that we 

 were enabled to examine the form of the larva. In some of these ova the larva could 

 be studied at the stage immediately preceding the rupture of the ovum ; in other 

 cases the free larvse were obtained. Length of larva, 3 Vth of an inch ; breadth, 

 ^Vth. When viewed from dorsal aspect, its shape appears ovoid (fig. 13). When 

 a profile view is made the ventral surface appears nearly flat, the dorsal very 

 convex (fig. 14). A pair of antepnse project from the ventral surface close to the 

 anterior margin. They possess indications of being three segmented, the terminal 

 one having at its free end a pair of long hairs. The limbs consist of two pairs ; 

 the anterior pair arises from the ventral surface, close to the antennae. Each 

 limb is bifid (fig. 15, A). The upper branch bears four or five very long hairs at its 

 extremity ; the lower, in addition to two long hairs at its free end, has a spinous 

 hook projecting from it. The posterior pair arises from the ventral aspect, nearer 

 the posterior than the anterior end of the larva. Each limb is shorter and thicker 

 than the anterior, and in none of the specimens examined could we see, on a 

 dorsal view, their extremities projecting beyond the lateral margin of the larva. 

 Each divides into two branches, one somewhat larger than the other (fig. 15, B). 

 A strong spinous hook, which appears to be capable of retraction within a 

 sheath, arms the branches of each limb. In addition to these appendages 

 the larva possesses a somewhat complicated arrangement, springing from the 

 ventral aspect, close to the posterior margin. It consists of a triangular prolon- 

 gation, folded over the posterior part of the convex dorsal aspect, so that the 

 apex only can be seen when the dorsal surface is looked dowi^ upon. It 

 gives off laterally three pairs of processes, each of which has connected to it 

 two lappets, bearing long pinnate hairs (fig. 16). It terminates by a lappet- 

 like process, which bears short, stiff hairs. The antennae, limbs, and tail-like 

 appendages, have transversely striped muscular fibres connected to them. The 



