696 SCIENTIFIC RECORD FOE 1884. 



plane, indicated by its anteroposterior axis. The arcbaeonomous or old- 

 fashioned type of the Clypeastridae as well as the neonomous or new- 

 fashioned Spatausidte give distinct indications of the bilateral form of 

 the adnlt. Thoujih more difficult to detect, this bilaterality obtains 

 also in the ancient Cidaridiie, and we have here " another instance of the 

 validity of the laws more than once ascertained to underlie evolution, 

 namely, that structures which are gradually bnt forcibly worked dut 

 during" the course of geological ages into specialized and highly char- 

 acteiistic features are virtually present within the fabric of the earlier 

 forms, though dormant, and, as it were, lying in abej'ance, and to be 

 detected only by a close scrutiny." 



In another place, in a discussion of the "calycinal system" (which is 

 defined as consisting of a central ossicle, five costals, and five radials), 

 Professor Loven speculates on the evolution of certain forms and parts. 

 ''^ llancMnnfi, with its enormous calyx, appears to be the most antique 

 of Echinoids. AVhile a number of fo^ms retain a stable relation of the 

 parts, we find that, when this is disturbed, the anal orifice is the first to 

 alter its josiiion ; it is followed by the madrei>oric and generative parts, 

 but the eyes remain stationary," &c. 



The manner in which changes may take place are summarized by the 

 author in the following terms : " A large and powerful structure, closely 

 specialized for alunction of fundamental importance in the economy of 

 some remote ancestral type, is inherited in an early state by a descend- 

 ant in which, from a total change in the mode of life, the very purpose 

 no longer exists for which it was originally contrived and to which its 

 parts were adapted. It long retains certain marked features which even 

 t© this day reveal its origin, but, unlike its Crinoidean sister-structure 

 which, with functions unaltered, nuiltiplies its components, it remains 

 simple as from the beginning, and superfluous as it has become, grad- 

 ually declines in intrinsic vigor, and is given up to subserving activities 

 that had no share in its i)revious existence. Invaded hy contending 

 organs and yielding to their various tendencies, it has its parts deeply 

 modified and p.ven to some degree suppressed, and although still true 

 to its type, and asserting, so to say, its unimpaired independence by 

 redintegrating its injured frame, it dwindles, nevertheless, from age to 

 age in every succeeding form and is seen to fall into decaj" and dismem- 

 berment and to lose one by one its characteristics, till at last little re- 

 mains of its original constitution." [E. Sve^iska Vet. Alad. Randl.,xix, 

 95 pp., pi. 21 ; J. R. M. S. (2), iv, pp. 751-754.) 



Holothurians. 



A large Holothurian. — The pharynx of a very large Holothurian, 

 dredged up in the Sulu Sea, has been described by Prof H. N. Moseley. 

 ^o traces of tbe rest of the animal were found, but the pharynx exhibits 

 unusual characters and the calcareous skeleton is remarkably developed. 

 It is, however, most noteworthy here on account of its large size, being 



