156 Dr. A. Philippi on the genus Serpula. 



1 Diet/ xlviii. p. 560*. [The description which Risso gives in 

 his 'Hist, de PEur. Merid/ iv. p. 405. is quite romantic, and 

 does not in the least agree with the statements of Cuvier in 

 'Regne Animal/ ed. 2. vol. iii. p. 192, whose description is 

 exactly in accordance with my own observations, which will be 

 detailed under b.'] 



b. The branchiae simply fan-shaped. Psygmobranchus, Ph. 



I cannot agree with Cuvier in referring the last section, to which 

 I have applied the name Apomatus, to Sabella. I would not lay 

 any great stress on the fact that the Sabellm form a membranous 

 or coriaceous tube, while Apomatus forms a calcareous one ; but 

 I consider of great importance the fact, that in the Sabella all the 

 rings of the body are formed alike and are provided with similar 

 bundles of bristles, while in Apomatus, precisely as in Serpula, 

 the first seven fasciculi of bristles are fixed in a membranous ex- 

 pansion, of which not a trace was indicated in the Sabella ob- 

 served by me. 



I will now pass on to the characters of the individual species. 



1. Serpula, L. (sensu strictiori). 



1. S. echinata, Gm., testa teretiuscula, protensa, flexuosa, rosea, 

 transversim rugosa, carinis denticulatis, echinata. Diam. 2'". 



Animal branchiis albo coccineoque fasciatis, filorum (in utraque) 30 

 et ultra, operculo rubro. Gm. p. 3744 ; Gualt. t. 10 R. ; Mar- 

 tini, 1. f.8. 



2. S. pallida, Ph., testa teretiuscula, protensa, flexuosa, pallide rosea, 

 carina mediana conspicua, laterali utrinque obsoleta, striisque in- 

 crement! tenuibus subaspera. Diam. 1^'". 



Animal branchiis albo coccineoque fasciatis, filorum pauciorum quam 

 in antecedente, operculo albido. 



3. S. triquetra, L. ? ? testa triquetra, flexuosa, alba, altero, latere tota 

 adnata. Diam. 2'". 



Animal branchiis albo coccineoque fasciatis, filorum circa 30 ; oper- 

 culo coccineo, crenis circa 24 (according to the drawing ; I forgot 

 to notice the number of folds). 



I do not however think that is the Linnaean species. Linnaeus 

 has not described the animal, and only saw small individuals ; the 

 subsequent citations of Baster, copied by Martini, Gualtieri and 

 others, do not exactly correspond to my species, as they represent 

 the shell much thinner. It should also be observed, that the shells 

 of Serpula triquetra, Vermilia triquetra, and Pomatoceros tricus- 

 pis are difficult to distinguish without the animals. Would it 

 therefore not be better to banish entirely the name Serpula tri- 

 quetra of Linnaeus ? 



* The figure of Seba (i. t. 29. fig. 1, 2) does not agree, as already ob- 

 served by Cuvier, with the diagnosis ; it wants the disque of Cuvier or the 

 thorax, " egalant au moins la moitiS de Pabdomen." 



