ANTHOMKIH'S.K STOMOTOfA. 113 



surface of the shells of Limulus, fastened to the sand-tubes of Sabfllarin. The stems are simple 

 and unbranched and are only about 0.2 mm. in height. They are covered for about two- 

 thirds of their length by a delicate, closely-adherent film of perisarc to which foreign particles 

 become attached. The stomach occupies about one-fourth or one-fifth of the length of the 

 stem from which it is separated by a slight constriction. Each polypite has 10 tentacles which 

 point alternately backwards and forwards, those pointing forwards being a little longer than 

 the others. The medusae are attached by very short peduncles to the sides of the stems. When 

 the medusa is set free it is about 0.5 mm. in height and there is no trace of the apical projection, 

 which develops in about eight days. 



In an abnormal individual medusa of this species found at Newport, Rhode Island, in 

 July, 1892, there were 4 long tentacles, i at the base of each of the 4 radial-canals. This 

 medusa was maintained alive in an aquarium for more than a month. When first found it had 

 only 2 long tentacles which were diametrically opposite one another at the bases of i of the 

 radial-canals. The other 2 tentacles developed later, after the first pair had attained their full 

 length. The medusa had then 4 radially placed tentacles and 12 rudimentary tentacle-buds. 

 This variation is interesting, as it illustrates the close relationship between Stiiniutrnu and 

 Turns. 



Stomotoca ruorjsa is common on the southern coast of New England in summer. It is 

 found all along the coast to southern Florida, but is not very common at Tortugas or among tin- 

 Bahama Islands. It has never been seen north of Cape Cod, Massachusetts. 



Rittenhouse, 1907, finds that the eggs of this medusa are laid between 5'' to 5'' 30"' in the 

 morning. The egg is chalky-white. The entoderm is formed by cellular ingression. The 

 planula settles down upon its side and becomes a branched hydrorhi/a from which the p<>!\ - 

 piles bud out. 



Stomotoca pterophylla Haeckel. 



Plate 2<), figs. 5 to ^; pl.Ue 30, fig. 7. 



Xtomotoca ptfroplnlla, HAKCKF.I., 1879, Syst. der Medusen, p. 52, taf. 4, fig. 10. 

 Xiumolorti persphyHa, F I:\VKKS, |SX<), Report Comrmss. Fish and Fisheries for 1X86, p. 524. 



Adult medusa. Bell conical, with widely flaring sides and small, sharply-pointed apical 

 projection. It is about 20 to jo mm. in diameter and 10 to 12 mm. in height. The gelatinous 

 substance is very thick at the aboral pole, but becomes thin at the bell-margin. There are 2 

 long, tapering, marginal tentacles which are situated at the bases of 2 of the radial-canals, 1 80 

 apart. When expanded these tentacles are full}- 10 times longer than the bell-diameter. In 

 addition to the long tentacles, there are about 60 to 80 small rudimentary tentacle-bulbs, 15 to 

 20 in each quadrant. The 4 radial-canals are wide, ribbon-like, and flat, with smooth, simple, 

 outer edges. The ring-canal is narrow and its upper edge is smooth. There is a very wide, 

 conical peduncle which extends about to the level ot the velar opening. The gastric part of the 

 manubi mm is large and swollen and lies mainly outside ot the bell-cavity. There are 4 promi- 

 nent, complexly crenulated, lanceolate lips. The gonads occupy 8 adradially situated, longitu- 

 dinal swellings upon the sides ot the stomach (plate 29, fig. 4). Each gonad consists ot a io\\ 

 of swollen, leaf-like ridges which trend in a transverse direction. The stomach and tentacle- 

 bulbs are brown. Radial-canals milky. There are no ectodermal ocelli. 



This species is found in the West Indies and the warmer parts of the Gulf Stream. I 

 found many specimens among the Bahamas and at the Tortugas during the spring and early 

 summer ot 1907. 



It is closely related to Stomotoca Jivisa, described by Maas, from the west coast of Mexico 

 (Mem. Mus. Comp. Zool. at Harvard College, vol. 23, p. n, tat. i. tigs, i i<j, 180,7). ' Hlt 

 its rich-brown entoderm distinguishes it from the Pacific species. 



Haeckel describes this medusa from preserved specimens, and this may account for 

 certain errors in his description and figure. A small apical projection appears to be con- 

 stantly present and there are no "ocelli." The radial and circular muscles of the velum are 

 very powerfully developed. In extreme states ot contraction of the bell the peduncle mav 

 extend beyond the velar opening or tall short of reaching it. The long tentacles are higlih 

 contractile and when expanded are reduced to mere thread-like filaments. 



