134 BULLETIN OF THE 



Newport, R. I., in the last of September. As the plutei undoubtedly 

 develop from ova laid by adults, which live within a short distance of 

 the laboratory, their date of appearance is not dependent upon those 

 causes to which we very probably ascribe the marked periodicity in 

 the times when Salpae and those animals which live in the high seas 

 revisit Narragansett Bay. 



Although it is not known whether Echinarachnius lays its eggs in all 

 months, or can be fertilized at all times of the year, it can be said that 

 in the last' five years in which I have kept my record of the times when 

 marine larvae appear at Newport, the greatest number of larval Echin- 

 arachnius appear in September. None were collected in June, in July 

 they are sporadic, and the largest number usually came in September. 

 Every one acquainted with pelagic fishing knows how much variation 

 there is in the time when pelagic larvae appear, and these statements indi- 

 cate only approximation. I suggest that they point to the end of August 

 as the probable time of ovulation at Newport of the Echinarachnius. 



The body of the adult pluteus is elongated, rounded on its anal 

 pole. On the opposite end it is continued into four pairs of arms, all of 

 which have calcareous rods, w^hile two pairs, pr and air, are latticed. 

 The latticed rods are the stoutest, and are known as the antero-lateral, 

 ah, and the posterior, /)r. The latter arise from the posterior side of 

 the body, and are fused with the system of rods which extends through 

 the body. A very prominent cluster of dark red pigment cells, ing, is 

 found near the distal ends of all the rods. Pigmentation of the same 

 color occurs in small granules along the length of the arms, and on the 

 body walls. The arms are skirted by a ciliated baud, on the edges of 

 which are small granulations. The ciliated band connects the two pos- 

 terior arms on the median ventral line. Laterally from these arms the 

 same band passes to the antero-lateral rods. 



No ciliated epaulettes were observed. In some specimens it was 

 noticed that the ciliated band in the connection between the two pos- 

 terior arras on the ventral side was so folded that we have a median and 

 two lateral lobes in the region of the band placed between the two pos- 

 terior arms. Something similar is figured in the pluteus of Echinocya- 

 mus by Miiller, but as Miiller says that ciliated epaulettes are not found 

 in his pluteus of Echinocyamus, we may conclude that the last men- 

 tioned bodies are not epaulettes in the closely allied Echinarachnius. 

 The antero-lateral arms, air, closely resemble the posterior in pigmen- 

 tation, latticed axes, ciliation, and size. The ciliated band continued 

 on them from the posterior arms is carried thence to the edge of the 



