309 



Stat. 88. June 20. o°34'.6N., ii9°8'.5E. Northern part of the Strait of Makassar. 1301 m. 



Bottom fine grey mud. i adult female, without eggs. 

 Stat. 211. Sept. 25. 5°4o'.7S., 1 20" 45.5 E. East of Saleyer Island. 115S m. Bottom coarse 



grey mud, superficial layer more liquid and brown. 1 adult male. 



It is with .some doubt that these specimens are referred to Prion, oimnatosteres, the 

 first described of the three species of this genus, at present known. The figure 4 in the 

 "Illustrations", however, seems to be inaccurate. According to Alcock's description of 1901 

 the median carina of the carapace extends to within a short di.stance of the posterior border, 

 in the figure, however, to hardly beyond the middle; the telson .should be scarcely as long as 

 the 6''^ abdominal somite, in the figure it is not shorter than it; the 4''' pair of legs, finally, are 

 described as a good deal longer than the 5* pair, in the figure the latter are but little .shorter. 



Both in Prion, pectinata Faxon from off Martinique and in Prion. Dojhini Balss from 

 Japan the eyepeduncles are present, transformed in Faxon's species "into a pair of closely 

 apposed trihedral processes, with acute and somewhat divergent tips", in the latter in two 

 tapering and pointed stalks, placed on either side of the rostrum and closely apposed ("als diinn 

 zugespitzte Stiele dicht nebeneinander"). In the present specimens (Fig. 76a) one observes, like 

 in Prion, pectinata (\V. Faxon, in: Bull. Mus. Comp. Zoology, Vol. XXX, X° 3, i S96, PI. II, 

 fig. 5), on either side of the rostrum a triangular process with acute tip, of which both the 

 outer margin and the upper surface are a little concave, while the two inner borders are at 

 their base probably contiguous, but they soon diverge, so that the apices are somewhat remote 

 from one another. Different, however, from the west-indian species, in the present specimens 

 the two processes are hardly longer than the rostrum, when the carapace is looked at 

 from above. In the last description of Prion, ommatostercs^ that of 1901, the eyestalks are 

 apodictically said to be wanting or "represented by a pair of microscopic tubercles on the 

 anterior edge of the exposed anterior somite". In the figure 4 of the "Illustrations" neither 

 the described triangular process, the transformed eyestalk, nor the pointed stylocerite of our 

 specimens are visible, but, the figure being apparently inaccurate, these two processes are 

 perhaps omitted. 



Rostrum triangular, acuminate, obliquely ascendant; when looked at from above, the 

 rostrum appears but little longer than broad at base, while its length proves to be in the male 

 one-ninth, in the female one- tenth the distance, in the middle line, betweea the tip and 

 the posterior margin of the carapace, the rostrum being in both specimens 0,84 mm. long. The 

 median carina is armed in the female with 6, in the male with 8 forwardly directed teeth and 

 reaches in the former to the posterior fourth, in the latter about to the posterior fifth of the 

 carapace; in the male the i"' or anterior tooth is slightly larger than the rest and the 5"' is 

 very small, while the 6 others are equal, but the 5"' tooth is perhaps damaged; the distances 

 between the , tips of the three posterior teeth are a little longer than those between the others; 

 this is also the case in the female, but the i^' tooth is here scarcely larger than the rest. 



Orbital spine small, acute, reaching not so far forward as the rostrum. Antero-lateral 

 angle of the carapace spiniform, reaching farther forward than the rostrum and fringed with 

 feathered setae as in Prion. Dofleini. 



