802 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [84] 



The individuals of this species are usually an opaque, ivory-white 

 color. A few in one of the hosts were observed to be tinged with a 

 greenish color. This may have been due, however, to the action of 

 some food which had been taken into the alimentary canal of the host 

 a short time before the specimens were collected. 



i 



LEG ANICEPH ALUM*, gen. UOV. 



[Aexavj'c, a platter.] 



Body taBniteform, articulate, head transversely flattened, circular or 

 subquadrangular, and consisting of two disciform plates. Posterior 

 plate with four supplemental disks (auxiliary acetabula). Neck short 

 or none. Genital apertures marginal. 



Van Beuedeu mentions (Poiss. des cotes Belgique, I, Parasit. et com. p. 

 19, Plate v, h'g. 13), among the parasites of Trygon pastinaca, a genus 

 which he names Diacobothrium. The name which he gives to the species 

 is D.fallax. He publishes no description of the worm, but figures the 

 head and anterior segments. The figure is a good one, but there is no 

 explanation of the number of times it is magnified. When, however, 

 one is obliged to choose between a short description and a good figure 

 in the identification of the Cestoda, the latter is to be preferred. Van 

 Beneden's figure of D.fallax shows it to be a Cestod, with a thick, mus- 

 cular anterior disk surmounting a quadrangular base, the angles of 

 which are prolonged into prominent, tubular bothria, the sucking-disks 

 of which are circular. 



Although I do not feel justified, from such meager data, in referring 

 a parasite, which I have obtained on three different occasions from the 

 spiral valve of Trygon centrum, to the genus Discobothrium, I yet find 

 sufficient resemblance between Van Beuedeu's figure and my specimens 

 to incline me strongly to the belief that they are closely related, if not 

 geuerically identical. The near relationship, if not actual identity, of 

 their hosts, makes the close affinity of these parasites the more 

 probable. 



19. Lecanicephalum peltatum, sp. uov. 



[Plate ix, Figs. 2-4.] 



Head nearly circular, disciform, and joined to the neck or anterior 

 part of the body at the middle of the posterior side, after the manner of 

 a peltate leaf. In the living worm the head looks like two thin plates, 

 placed the one on top of the other. The anterior plate is almost circu- 

 lar with their edges, which are more or less ruffled or irregularly creii- 

 ulate. In preserved specimens they are sometimes so much folded at 

 the edges as to obscure the characteristic disciform shape. The second, 



* The genera Lecanicepltalum and Tylocephaliim are put among the Tetrabothriidos 

 although neither genus possesses the characteristic bothria of the family. It may 

 become necessary, upon further examination of theso interesting forms, to put them 

 in a distinct group under the name Gamobothriida; or some equivalent term. 



