54 HUBERT LYMAN CLARK ON 



nitric acid. Corrosive-sublimate alone gave poor results, while Perenyi's fluid proved 

 very unsatisfactory, the material prepared with it showing only fair preservation, and 

 staining very poorly. Very good material for the study of the calcareous bodies and 

 the development of the calcareous ring was obtained by the use of absolute alcohol. In 

 staining, it was found useless to try any solution which contained less than seventy per 

 cent alcohol, collapse and distortion of the tissues always resulting. Kleinenberg's 

 haematoxylin and eosin gave good results, but acid borax-carmine (70% alcohol) and 

 Lyons blue (70% alcohol) proved the most satisfactory. The early stages of the larvae 

 were oriented and imbedded in celloiden before imbedding in paraffine, and thus kept 

 their shape very well. Although material was so abundant and easily obtained, it is 

 impossible to tell the age of the different embryos, for none of the eggs obtained 

 developed beyond the blastula, and later stages would live outside of the mother for only 

 a very short time. Accordingly it cannot be determined how many days or weeks are 

 required for the growth of the pentactula or older stages, though there is reason to 

 believe that growth, at least early in life, is very rapid. 



2. HISTORY AND SYSTEMATIC POSITION OF SYNAPTA VIVIPARA. 



The Danish naturalist Orsted ('50) mentioned the discovery in the West Indies of 

 a new genus of the Synaptidae, the chief characteristic of which was its being viviparous. 

 To this genus he gave the name Synajjtula, and the type species he called vivipam. In 

 his very brief and unsatisfactory account, for which I am indebted to Ludwig's German 

 translation ('81), he mentions the occurrence of the form in " shallow-water," describes 

 the color as "greenish," and speaks of the presence of " eyes," "skin-glands," and 

 "anchors." He never published anything further in regard to the species, and later 

 writers, as Bronn ('60), Selenka ('67), and Semper ('68), accepted the genus Synaptula 

 without comment, But Ludwig ('81), in describing a viviparous Chirodota (G. rotifera) 

 from the coast of BraziJ, suggested that it might be the species on which Orsted had 

 based his new genus. This conclusion was adopted by Lamport ('85), and in his work 

 we find Synaptula vivipara given as a synonym under hirodota rotifera. Theel ('86) 

 placed Synaptula vivipara in the list of Synaptidae about which little or nothing is known, 

 but he suggests in agreement with Ludwig ('81) that the stage of development which the 

 eggs reach before leaving the mother, is not a satisfactory character upon which to base 

 a new genus. Ludwig ('86) described a small Synapta, found in floating seaweed, west 

 of the Abrolhos Reef, Brazil, which he regarded as identical with Orsted's species, since 

 it contained young in the body-cavity and answered Orsted's description, except in color 



