158 Prof. M4ntosli's Notes from the 



with young Arenicola, the little boring Sipunculus, Pholoe, 

 and swarms of Polydora ciliata at the East Rocks, St. An- 

 drews, the body, in spirit^ is rounded in front, but the poste- 

 rior third is more or less flattened, as in Heterocirrus. The 

 colour of the two regions also differs, that in front being 

 pale greyish, whilst the posterior is brownish red. The 

 bristled segments are about 35 in number. The snout is 

 formed as in the adult, with the mouth considerably behind, 

 and the tentacles and the branchiae are well developed. The 

 two rounded papillse at the vent are more distinct than in 

 the adult. The characteristic hooks show that whilst the 

 flattened posterior region simulates that of Heterocirrus ater, 

 the form is essentially ditf'erent. 



No feature in Guernsey and Herm is more interesting in 

 the littoral region than the abundance of boring forms in the 

 coating of Lithothamnion on the surface of the hard gneiss, 

 especial!} at low water. Amongst them is the next form, 

 viz. Dodecaceria ater, De Quatrefages (which is not a variety 

 of Dodecaceria conchariim, which also occurs in the fissures 

 of the rocks in long galleries curved in various ways). 

 Langerhans * and De St. Joseph consider this only a variety 

 of D. concharum, but so marked a variety, especially in regard 

 to the structure of the hooks, merits in the meantime special 

 separation. It may be that Langerhans had not the present 

 form before him, for his figure of the hooks of D. concharum 

 is good. The head of this species is rather elongated, like 

 that of Phyllodoce, slightly tapered and smoothly rounded iu 

 front, and with two dark patches of minute eyes in the 

 median dorso-lateral region, the snout in front of these 

 generally being pale in the preparations, whilst that behind 

 is dark. The mouth opens ventrally a short distance behind 

 the tip of the snout, as in other forms, and not at the tip as 

 De Quatrefages observes. 



The body is 1-2 inches long, rounded or slightly flattened 

 in front, more distinctly flattened after the anterior third, 

 and often forming a broad oar-like region posteriorly before 

 abruptly narrowing toward the tip, which presents a papilla 

 on each side of the vent. It is slightly tapered toward the 

 snout and the segments throughout are distinctly marked, 

 their antero-posterior diameter being larger iu front than 

 behind, though the first four or five bristled segments are 

 narr-ow. The colour is of a very dark blackish green 

 throughout, the tentacles being pale green, with a central 



* Zeitschr. f. w. Zcol. Bd. xxxiv. p. 96. 



