298 DR J. H. A8HWORTH 



to this genus lacks eyes and aeuropodial cirri, and in these respects, as well as in the 

 form of the anal cirri, and the chfetfe of the first and second notopodia, it differs 

 from the Scotia Bay specimen. 



The structure of Oncoscolex is also imperfectly known, but, as represented 

 by the type-species 0. dicranoch&tus Schmarda, it differs from the Scotia Bay 

 specimen, for in the former the segments are composed of not more than three rings, 

 the parapodia do not bear cirri, and stronger chsetse are not present in the first and 

 second chsetiferous segments. 



The specimen under consideration cannot, therefore, be referred to any of the 

 four genera just discussed, nor do its characters entirely agree w r ith those generally 

 accepted for the genus Sclerocheilus. The differential characters of this genus, as 

 represented by the type-species, S. minutus Grube, have been emended and stated 

 thus by SAINT -JOSEPH * : Prostomium small, with thick lateral processes and with 

 eyes ; notopodium and neuropodium of first ehsetiferous segment bear capillary 

 chsetse and, a little above the neuropodium, five or six large, retractile, curved 

 acicula, together with an e<jual number of slender and shorter acicula ; the para- 

 podial rami of the other segments bear capillary and furcate chsetse ; small neuro- 

 podial cirri are borne on the last segments only ; anus surrounded by five or six 

 cirri ; gills absent. 



I have recently re-examined the series of specimens of S. minutus at my dis- 

 posal, and have also, by the courtesy of Professor ANT. COLLIN, had the privilege of 

 examining the entire series of the original specimens collected by GRUBE, and 

 preserved in the Konigliches Zoologisches Museum, Berlin, and am able to modify 

 and supplement the characters given above. 



OBSERVATIONS ON SCLEROCHEILUS MINUTUS GRUBE. 



The prostomium (fig. 7) is drawn out antero-laterally into two stout processes, 

 and bears eyes dorsally. The eyes t vary in development in different specimens ; in 

 some they are comparatively small, and the right and left eyes are separated by a 

 distinct interval, but in other specimens they are larger, and in several cases are in 

 contact, or are actually fused in front, forming a A-shaped, brown pigmented area. 

 Near the posterior margin of these large eyes there is, on one or both sides, a simple 

 eye, about 9/x in diameter, consisting of a cup-shaped mass of pigment-spherules and 

 a spherical lens. This eye is situated below the epidermis, on or in the brain, and 

 is therefore not seen except in cleared specimens. 



Between the prostomium and peristemium there is on each side a protrusible 



of the genera Lipobranchius and Eumenia is required, and the relationship of L.jeffreysii to E. crassa should be re- 

 investigated. I have collected considerable material in view of undertaking such revision, but until I have the 

 opportunity of examining certain types, which have been imperfectly described, the work is necessarily at a standstill. 



* Ann. Sci. Nut. Zoul., vii Stir., tome xvii (1894), p. 104 et seq. 



t For an account of the structure of the eyes, see A. et L. DEHORNE, Arch. Zoul. Exper., tome liii (1913), pp. 85-90. 



(HOY. soc. EDIN. TRANS., VOL. L, 410.) 



