532 Prodromiis of the 



from nmbellseform to infundibnliforra or nrnaeform ; the 

 aboral side at the centre extended into a monocamerous or 

 tetracamerous pedicel, whose base constitutes the principal 

 means of attachment and progression ; the middle of the 

 oral side extended into a cylindrical quadrate mouth, with 

 plicate lips ; the oral and aboral sides of the disc consist 

 each of two walls, between which is included a gelatini- 

 form layer of varying thickness, which in the aboral side, 

 although compressible and resilient, is uncontractile, but 

 in the oral side is contractile, and constitutes the musculo- 

 gelatiniform layer, which is also continuous into the tenta- 

 cles and marginal anchors, between their outer and inner 

 walls, whilst the aboral gelatiniform layer is continuous 

 into the pedicel between its outer and inner walls ; the 

 cavity of the disc divided into four quadrant camera3 by 

 the junction of the oral and aboral sides along four 

 equidistant lines, thus forming so many partitions which 

 extend from the base of the four flanks of the quadrate 

 moulh nearly to the intertentacular margin ; the discal 

 camertc either simple (Eleuthero carp idee), or each subdi- 

 vided into two superposed spaces ( CleistocarpidcE) by a 

 horizontal membrane or diaphragm, which extends from 

 the base of each of the four angles of the mouth to the 

 distal ends of the approximate halves of neighboring gen- 

 itals ; exteriorly the oral side of the disc is divided into 

 four depressions, corresponding to the region about the 

 four partitions, and four elevations alternating with the 

 latter, and constituting the four buttress-like basilar ex- 

 tensions from the angles of the mouth : in the area of the 

 four depressions are situated the four principal muscular 

 layers ; in the region of the four elevations are the four 



ings Boston Soc. Nat. Hist., May 18G2, p. 47, in which 1 iiiive attempted to prove 

 that the Luccniarians arc a distinct order of Acalejihiv. I take occa.sion here to 

 correct a provoking error in the paper referred to: on the 53d page, line 8, /ess 

 should bo move. 



