Studies on marine Ostraccds 



539 



I nmmpleteness nf 

 ihf deacription. 



Remarks: — The re-description of A. ahyssicola given above is based on an investigation Material. 



of a single specimen, a female with large eggs in the brood chamber, which was kindly placed 

 at my disposal by Professor G. O. Saus and which was denoted by this wTiter as the type specimen 

 of this species. It is certain, however, that this statement of G. 0. SaRS's was not quite correct. 

 This is shown by the fact that the specimen sent to me was not dissected, while the original 

 description was obviously made from a dissected specimen. The specimen investigated by me 

 is probably, however, one of the two specimens that G. 0. Sars mentions 1870, p. 171: ,,Kun 

 2 Exemplarer af denne lille Cypridinide toges ved Guldbrands0crne paa 120 Favnes 

 Dyb."* This is supported by the habitat, among other things: ,, Lofoten 120 F." The 

 preparations of the dissected type specimen have, according to what Prof. SarS replied to an 

 enquiry of mine, been certainly irrecoverably lost. It seems, however, to be beyond all doubt 

 true that the specimen re-examined by me belongs to this species. 



As the specimen in question was somewhat defective I was unfortunately not able to 

 give such a complete description of the species as is desirable, but I hope that in spite of the 

 incompleteness the description will permit of a certain identification of the species. The 

 characters that could only be described incompletely or to which a certain amount of uncertainty 

 is attached are as follows: The medial bristles of the shell; the number of bristles on the 

 anterior side of the original third joint and the equipment of the bristles of the end joint of the 

 first antenna; the number of bristles on the end joint of the exopodite of the second 

 antenna; the bristles on the sixth limb and the number of f u r c a 1 claws. With 

 regard to the number of bristles on the end joint of the exopodite of the second antenna 

 it may be pointed out that on this antenna of one side — on the other side the two distal joints 

 on the natatory branch were missing — three bristles were observed on this joint, one long 

 one and two short ones, the two latter of about the same relative length as the two short ones 

 in figure 5 of A. Gnmaldi. I did not succeed in deciding with certainty whether an additional 

 (long) bristle had existed originally, in other words if this joint is characterized by four bristles, 

 the usual number in species of this genus. It seems, however, very probable to me that this 

 was the case. The sixth limb is certainly of the same type as is usual for this genus, 

 with a large number of ventral bristles. Both the f u r c a 1 lamellae were armed with eight 

 claws. But this organ seemed to be somewhat damaged behind the posterior claws, so that 

 I am not C|uite certain whether one or more additional claws may not have existed originally. 



As will be seen fi'om a comparison there is a close resemblance between G. 0. Sars's i>'ll'-renref beiaecn 

 original description and the re-descnption of this species given by me above, i here are, however, ^.^^^^ ^^^^ ^^_ .^ . 

 a number of difEerences. Thus G. 0. Sars states that the shell is only 1,32 mm. long, while, 

 as is seen above, I found it to be 1,63 mm. At present of course I cannot express any certain 

 opinion as to whether this difference in length is due to the fact that the specimen measured 

 by G. 0. Sars was a lai-va or if the species is subject to such great variations in length at the 

 same locality. But the fact that, if we assume the specimen measured by G. 0. .Sars to be 

 a larva in the first stage, we obtain a coefficient of growth of 1,23 (1,63 : 1.32 = 1,23), i. e. about 

 the same coefficient as I found for other closely-related forms [A. Grimaldi, Cypridina (Doloria) 



*OnlyUvospe(inuMisof tliissnuill C \ p r i d i n i d wero takon at theGuldbrand islands at a di-pth of 120 fattionis. 



