50 Prof. M'lntosh's Notes from the 



those of Oligoclipets. The shaft is long, gently curved, 

 tapered infenorly, dilating at its distal third into an indis- 

 tinct shoulder, from which it is gently tapered to the throat 

 below the main fang. The neck is stout and nearly straight, 

 and the main fang, which arises at a wide angle to the neck, 

 is blunt, whilst on the crown, which slopes downward in 

 lateral view^ are a few small teeth. Under pressure the hook 

 often lies so as to give an autero-posterior outline, which is 

 hastate, a constriction occurring behind the great fang, 

 from which a gradual enlargement occurs to the shoulder, 

 beneath which it again tapers to the base. The usually 

 acute Claparede had overlooked these organs. The terminal 

 hook of the row shows a more simple form, without spikes in 

 the crown. The posterior hooks are large and avicular, 

 are identical with the type as figured by IMalmgren, have a 

 base much produced anteriorly, the anterior outline of the 

 neck curving from the main fang in a convex manner down- 

 ward to a blunt prow, the inferior outline being slightly 

 concave, as also is the posterior outline. The main fang 

 is long and sharp, and above it is a comparatively large 

 secondary tooth. 



This is, in all probability, the Myxicola steenstnipi of 

 Kroyer *, though the description is so lax that it is difficult 

 to be certain. He did not observe the hooks. 



A Myxicola procured between tide-marks, Herm, in 1868, 

 offers certain peculiarities distinguishing it from M. infun- 

 dibulum and M. viridis, as well as M. dinardensis of 

 De St. Joseph, though the absence of anterior hooks leaves a 

 margin of doubt in relation to the last-mentioned. It is 

 a small form, measuring about | inch in total length, and 

 having the typical condition of the cephalic region and collar. 

 The branchise are of moderate length, and have broader wings 

 and less tapered tips on the distal processes of the filaments 

 than in M. wfandibuliim. 



The anterior region seems to be short, as in M. dinardensis, 

 which has only three segments, and in the specimen from 

 Herm the long crotchets appeared to have only a single tooth 

 above the main fang, as in M. viridis. The posterior hooks 

 came far forward, and in structure they diflered from those 

 of their allies, for the main fang is proportionally larger and 

 the tooth above it is only about half its length, and thus 

 contrasts with the condition in other forms. The basal 

 region has a nearly straight inferior border, to which the 

 prow curves downw^ard. 



* Oversigt Kgl. dauske Vidensk. Selsk. Forhaudl. 1856, p. 35. 



