368 HAWAIIAN AND OTHER PACIFIC ECHINI. 



PARASALENIA. 



v 



A. Agassiz, 1863. Bull. M. C. Z., I, p. 22. 

 Type-species, Parasalenia graliosa A. Agassiz, 1863, 1. c. 



This is a very interesting genus and its affinities are by no means clear. The 

 ambulacra are echinoid, the anal plates are like Arbacia, while the form of the 

 test is like Echinometra. The spines are externally like Echinometra and the 

 differences internally are hardly as important as Me Intosh and Mortensen seem 

 to think. When compared with Echinometra-spines of the same size, those 

 of Parasalenia are not essentially different. The lantern, teeth, and auricles are 

 like those of small Echinometras, except that there are apparently no projections 

 on the epiphyses for the support of the teeth. It is clear from these important 

 structures about the mouth, that there is no near relationship to Arbacia, and 

 the pedicellarise confirm this conclusion. Except that the lateral tooth is lacking 

 on the left side of the narrow blade, there is nothing about the globiferous pedi- 

 cellarise to distinguish them from those of Echinometra, and the other forms 

 are even less peculiar. The calcareous spicules in the pedic"els of Parasalenia 

 are very characteristic but they do not indicate relationship to any othe r group. 

 On the whole it seems that Parasalenia is an isolated offshoot from the echinid 

 stock from which the Echinometridse have sprung and that it is not properly a 

 part of that family from the phylogenetic point o f view, but as a matter of con- 

 venience it may be placed therein. 



Whether the genus contains more than one valid species seems uncertain. 

 Owing to insufficient material the status of Pohlii is doubtful. Typical specimens 

 of the two nominal species are very different but as is so often the case, there 

 are certain specimens which are perfectly intermediate at least in many ways. 

 The red coloration of Pohlii is very noticeable and extends even to the calcareous 

 matter in the pedicellariae but specimens of gratiosa are sometimes quite red, 

 especially when young. The primary spines of graliosa are sometimes banded 

 and if such specimens are also more or less red, the resemblance to Pohlii is very 

 marked. In our specimens of Pohlii, genital 3 is excluded from contact with the 

 periproct, by the meeting of genitals 2 and 4, but whether this is a constant 

 specific character, is not known; if it is, it is an excellent one. In our specimens, 

 globiferous pedicellarise are extremely rare, and tridentate fairly common in 

 gratiosa, while in Pohlii, the globiferous are abundant while the tridentate are 

 very rare; but it may be doubted if this difference holds thoughout the species. 



What seem to be the real specific differences may be stated as follows : 



