CASTALIA PUNCTATA. 



121 



The term Castalia was indicated by Savigny 1 in 1820 as suitable for the Nereis 

 rosea of 0. Fabricius, and therefore has priority over Dr. Johnston's title Psamathe 

 (1836), 2 and though the species described by the authors are different, there is no need to 

 separate them generically. In the original description of Dr. Johnston the proboscis was 

 described as edentulous, and the feet as uniramous, but OErsted 3 pointed out the presence 

 of teeth, and showed that the feet were really biramous. 



Grube 4 (1879) observed that the genus was readily divided into two groups, in the 

 first of which the dorsal division of the foot has from three to five bristles, whereas in 

 the second the dorsal division has few and very small bristles — sometimes only one or 

 two spines. 



1. Castalia punctata, 0. F. Miiller, 1788. Plate XL VI, fig. 2; Plate LXIX, fig. 14- 

 foot ; Plate LXXVIII, figs. 2-2 b— bristles. 



Specific Characters. — Head somewhat square, pale yellowish, with two closely 

 approximated red eyes on each side, the anterior pair obliquely elongated and wider apart 

 as well as showing a cuticular lens anteriorly. Two slender tentacles on the anterior 

 border ; external to each is a palpus with an enlarged basal segment, and a more slender 

 distal region separated by a shoulder. Three pairs of long slender tentacular cirri, each 

 arising from a prominent ceratophore on first three segments. Body about an inch long, 



Fig. 47. — Muscles of Castalia punctata, O. F. M., as seen in section of the body-wall. 



most massive anteriorly, gradually diminishing posteriorly, where it terminates in two 

 long cirri. Colour of dorsum dull yellowish, crossed transversely by dark belts which 

 become only touches posteriorly. The posterior two thirds is tinted olive from the 

 intestine. Ventral surface dull yellow or salmon- colour, with a brown stripe in the 

 median line, which increases in density posteriorly. The attenuated cirri are pale. 



The proboscis is firm, barrel-shaped, with a broad median notch ventrally, flanked 

 by an elevated ridge with a papillose edge (ten papillse — Sars), and with four prominent 

 papillas along the dorsal arch. Foot biramous, the dorsal spine piercing the base of the 

 dorsal cirrus, which has a ceratophore, and is of proportionally great length, diminishing, 

 however, from before backward. Dorsal bristles slender, pale, tapering, and simple. 



1 ( Syst. Annel./ p. 45-46. 



2 ' Loud. Mag. Nat. Hist./ ix, p. 14. 



3 'Annul. Dan. Consp./ p. 23. 



4 e Schles. Gesell./ loc. cit. 



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