362 STAUROCEPHALUS CILIATUS. 



The feet do not alter materially in character posteriorly, except that the lower part 

 of the setigerons process at the exit of the inferior bristles is more prominent. 



Reproduction, — The specimen is a female, with comparatively early ova (July). On 

 the other hand an example from Plymouth, kindly sent by Dr. Allen, had fairly developed 

 ova in June. 



This species approaches Keferstein's Prionognathus ciliatus, and it may be that the 

 differences are due to imperfections in description and figures. The additional pair of 

 small eyes behind the tentacles is a marked distinction, though variation may occur in this 

 respect, yet in colour, structure of feet, bristles, and other parts, it closely corresponds. 

 The description of the teeth, however, differs, and he figures the ventral bristles as having 

 a simple instead of a bifid tip. Moreover, Grube places weight on the occurrence of only 

 two eyes, which is the condition, for instance, in his 8. bioculatus from Costa Rica. 



This appears to be distinguished from Claparede's S. Ghiaji by the presence of only 

 two eyes, by the much longer palpi, and the shorter tentacles, by the absence of the dorsal 

 peristomial papilla, by the absence of the elongated spines on the simple bristles, by the 

 absence of boldly serrate compound bristles, and in other particulars. 



So far as can be observed the Staurocephalus pallidus of Langerhans 1 approaches 

 closely to S. ciliatus, Keferstein, and this conclusion is borne out by an examination of an 

 example from Plymouth, kindly sent by Dr. Allen. The example has two very distinct 

 eyes at the inner border of the tentacles. 



Claparede and Mecznikow 2 describe and figure a young example of the allied 

 Staurocephalus Ghiaji, 0*8 mm. long, with two projecting lateral lappets of the pro- 

 stomium, and a pair of unjointed tentacles with palpocils at the tip. The dental appa- 

 ratus is present, and there are two dorsal organs on the peristomial segment. The feet 

 are fairly formed with a jointed dorsal cirrus. 



Another form, which may be termed provisionally Staurocephalus B, requires a brief 

 notice : — 



Habitat. — Procured in a trammel net off Fermain Bay, Guernsey, in July, 1868. 

 The net was placed at a considerable depth — near the bottom. 



Head furnished with four red eyes, and probably having the typical structure, though 

 such was not observed in the example, which was injured. 



Body elongated as in Staurocephalus Kefersteiui, and of a pale yellow hue, brownish 

 from the intestine, posteriorly. A line of white pigment passes along the middle of the 

 dorsum from the proboscis backward. Posteriorly the line becomes double from an 

 intervening streak and disappears towards the tip of the tail. 



The feet closely agree with those of Staurocephalus Kefersteiui in regard to general 

 outline, the proportions of the dorsal and ventral lobes (the latter being somewhat smaller 

 and more elongate), and the structure of the bristles. The compound series inferiorly 

 show the same very minute secondary tooth below the distal hook. The bifid bristles 

 of the upper part of the setigerons process are identical, the only difference observed 

 being the absence of the curve in the slender tapering bristles of the upper series, 



1 ' Zeitschr. f. wiss. Zoo!./ xxxiii, p. 300, Taf. xvi, fig. 35, 1869. 



2 Ibid., xix, sep. abd., p. 24, Taf. xv, fig. 3. 



