[127] NOTES ON ENTOZOA OF MARINE FISHES. 845 



* 

 0.005 mm in length, or one-eighth the length of the large hook. Oh the 

 opposite side they are slender, slightly recurved, and about 0.015 1 " 1 " in 

 length. 



The narrow crimson band at the base of the contractile bulbs is 0.02 mm 

 wide, and occupies the entire breadth of the body. The elongated rod- 

 like segments which immediately precede the mature segments contain 

 a double row of large, elliptical bodies, lying one on each side of the 

 median line. The cirrus is smooth, slender, of' moderate length, and 

 opens about the middle of the margin of the segment. The interior of 

 the mature segments is filled with the very numerous ova. 



This Rhynchobothrium is evidently the adult form of a species either 

 identical with the larval Rhynchobothrium from Gepola rubcscens figured 

 by Wagener (Nov. Act., Nat. Cur., xxiv, Suppl. 48 and 82, Plate xix, 

 230-234), or at least closely related to it. 



The figure of the proboscis given by Wagener shows the same re- 

 markable peculiarities which characterize this species. The shape of 

 the bothria, the proportions of the head, neck, proboscides, contractile 

 bulbs, as shown in Wagener's figures, agree with these specimens from 

 Trygon centrum. Wagener does not give a specific name to the larval 

 form. He simply designates it as "A Tetrarhynchus from Gepola rubes- 

 censP 



So far as I am aware, the adult has not been found. I therefore pro- 

 pose, as a proper specific designation for this species, the name R. ivag- 

 eneri, in honor of the original describer of what is probably the larval 

 form of the species. 



35. Rhynchobothrium lomentaceum Dies. 



[Plate xin, Fig. 1-3.] 



Diesing, Syst. Helm., I, 571 ; Rdvis. des Cepth. Par., 290. Von Linstow, 

 Comp. Helm., 280. 



I refer a single Rhynchobothrium from Mustelus canis to Diesing's R. 

 lomentaceum from M. vulgaris. This is done with some hesitation, for, 

 although it does not disagree with Diesing's description, the latter is 

 confined to such general characters that specific differences might still 

 exist between my specimen and R. lomentaceum. It should also be re- 

 marked that the armature of the proboscides resembles very closely that 

 of R. caryophyllum Dies, from Scoliodon lalandii. (Denks. der kais. 

 Akad., xn, 30, Plate iv, figs. 16-20.) 



Diesing gives the following description of R. lomentaceum: 

 Head with oval, lateral bothria converging at the apex. Neck slightly depressed. 

 Body lanceolate, first segments very short, transversely oblong, each with rounded 

 margin and swollen in the middle. Genital apertures. . . . Length of head and 

 neck, 4 mm ; length of body, 36 mm ; breadth of posterior, 4 mm . 



My specimen consists of the head, neck, and a few of the first seg- 

 ments, the whole measuring, when living, 9 mm . There is also a frag- 

 ment containing a number of jnediau segments and measuring, wlieti 



