278 



MR. H. A. BAYLIS AND LT.-COL. CLAYTON LANE ON 



A¥e believe, as has been stated above, that the male form 

 described by Molin under the name of Echinocej^halus uoicinatus. 

 is leferable to this species. The host, in this case, was Trygon 

 hrucco. Among our own material there are specimens from the 

 stiiig-rays, Ti^ygon lualga and Urogymnus asperrimus, which 

 appear to belong to the same species. 



From their size (13'7 mm. in length) von Linstow's examples 

 seem to have been immature, and few details are given of their 

 internal stucture. We will therefore give a fuller description 

 based upon our own material, chiefly upon the specimens from 

 Urogymnus. 



The worms are rather long and slender in general appearance. 

 The largest female in our possession is not quite mature. 



The lips (text-figs. 25 k 26) are large, very prominent and 

 massive, each consisting of an outer portion bearing the three 

 papillfe, and internally a rounded middle, and a dorsal and a 

 ventral triangular, tooth-bearing lobe. These lobes meet those 

 of the other lip and guard the mouth. The middle lobe is 

 without teeth, while the other lobes are each provided with an 

 internal thickening of the cuticle which is produced into tooth- 

 like ridges (text-fig. 28). The teeth interlock, as in Tcmquciy 

 with those of the opposite lip. The posterior surface of the 

 dorsal and ventral lobes bears a row of small tooth-like serrations 

 (text-figs. 25, 26, ser.). 



The head-bulb (text-figs. 25, 26) is distinctly' marked oflf from 

 the neck, and is visible to the naked eye as a little knob. The 

 hooks (text-fig. 27) are very minute and very numerous. They 

 are arranged in from 30 to 40 transverse I'ows, each row containing 

 a. very large number (several hundreds) of hooks. . The rows are 

 not always complete circles, but sometimes break oflf suddenly, 

 while dichotomous branching of the rows is not infrequent. 



The cuticular striation on the body is very fine, von Linstow's 

 statement that the oesophagus is only of the body-length 

 appears unintelligible, uidess it is a misprint for and even 



in this case it does not agree very well with our own measure- 

 ments. 



Of the eight pairs of caudal papillae in the male (PI. IV. fig. 

 17), those of the first pair are small and lateral, the second pair 

 more ventral. Pairs 3 to 6 form a group on either side of the 

 anus, the 6th pair being apparently adanal. The 5th pair is 

 situated somewhat more laterally than the rest. These four pairs 

 are placed close together, but a, longer space separates pairs 2 

 and 3 and pairs 6 and 7. The 8th pair is separated by a, very 

 long interval from the 7th, and stands quite far forward, these 

 last two pairs being both preanal. All the papillse, except the 

 small first pair, have a somewhat swollen base, not unlike 

 the structure seen in Tanqua, though less strongly developed. 

 The stout spicules (PL lY, fig. 17) are very slightly unequal in 

 length, the left being the longer. Each spicule terminates in a* 

 smooth, conical point (PI. lY. fig. 18). 



