Gatti/ Mirnie Laboratory ^ St. Andrews. 207 



Ehhrsia cormita, II. Rathke, var. h/jstricif. 



Drodf^od ii\ 92 fathoms oti Adventure Bank in the ' Porcu- 

 pine' expedition of 1870. 



Tlie liead generally resem!)les that o£ S/jJlis annil^aritf, 

 O. F. M., though the tentacles, like the cirri, seem to be 

 shorter. 



Tlie body also agrees with that of S. armiUaris, the cirri 

 being comparatively short. The foot has dorsally a cirrus of 

 seven to nine joints. Beneath is a short and bluntly conical 

 setigerous region b-aring spines and a group of bristles with 

 somewhat slender shafts slightly curved at the tip, which is 

 bevelled. The terminal piece is proportionally long and 

 with a hook at the tip and a minute secondary process 

 beieath. The edge of the termin.il piece has a series of 

 spikes. In this small specimen the cliaracters of the bristles 

 are less evident than in the larger, especially the discrimina- 

 tion of the secondary process beneath the terminal hook. 

 'J'iie ventral cirrus is elongated, the base somewhat con- 

 stricted below the enlargement, then tapering to the tip, 

 which extends as far outward as the end of the setigerous 

 region. 



This variety differs from the typical form in the shorter 

 dorsal cirrus and in the shorter ventral cirrus, whilst the 

 sUnderness of the bristles and the difficulty of diagnosing 

 their bifid nature brings it close to those species with simple 

 tips to the terminal pieces of the bristles which Langerhaus 

 has described *. As the latter author has pointed out, the 

 ChatosjjUis (Erstedi of J\Ialmgren f seems to be the sexual 

 form (witii swimming-bristles) of this species, procured in 

 June at iSjjitzbergen. Langerhaus also includes the Syllis 

 iexocidata of Ehlers \ under the same species, and they 

 certainly approach each other very closely, for palpi, cirri, 

 and bristles all correspond. 



In the typical Ehlersia cornuta, which was dredged in the 

 ' Porcu])ine ' expedition of 18G9 of}' Bundoran, Donegal Bay, 

 in 20-25 fathoms (Stat. 18), the form of the body is more 

 robust, the spikes on the edge of the terminal blade of the 

 bristles better marked, and the minutely bifid tip distinct. 

 The dor.sal cirri are stout and the ventral cirri are tongue- 

 shaped, and not long tapered cones as in this form (var. 

 hi/stricis), which approaches Syllis abyssicola in this respect. 



* Zeitschr. f. \v. Zoul. Rd. xxxii. p. 538. 



t Anu. Polycliiet. p. Ifi2. 



\ Hor.teuw! i. p. -241, pi. x. figs. •">, 7, i^ 3 (1864). 



