22 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
digitate tentacles, etc.,” from “the typical species of synapta,” which “have 15 tenta- 
cles and prominent verrucse.” This proposed genus has not been accepted by any 
writer on holothurians, because the form of the body and the prominence of the 
verrucfe are so closely connected with the degree of contraction of the muscles that 
they are virtually worthless as characters, while the number and shape of the tenta- 
cles differ in different species to such an extent that generic distinctions can not be 
based exclusively on them. Since Yerrill proposed his genus Leptosynapta three 
species of synapta with normally 13 tentacles, one with 11, and two with 10 have been 
described, and species with 20 and 25 are also known. Doubtless the genus Synapta 
as at present constituted includes two or more natural genera, but Yer rill’s genus 
Leptosynapta is not sufficiently well characterized to stand. The same year in which 
this change was proposed saw the publication of Selenka’s (’67) well-known mono- 
graph 'on the Holothurians. He pointed out that the name tenuis had been used for 
a synapta by Quoy & Gaimard in 1833, and accordingly suggests ayresii as a name 
for the form Ayres had called tenuis. He gives girardii Pourtales as a form from 
Cape Florida, evidently having read the original description hastily or carelessly, and 
he entirely overlooks its similarity to tenuis Ayres. In addition, he describes a species 
gracilis from Boston Harbor, which, as Theel (’86) has pointed out, is obviously based 
on specimens of tenuis Ayres, in which the calcareous bodies have evidently undergone 
some change due to the alcohol or other preservative used. 
In 1874, Yerrill (’74) gives the commonJSTew England synapta the name Lepto- 
synapta girardii , accepting Selenka’s objection to the name tenuis and recognizing 
the fact that Selenka’s names ayresii and gracilis are but synonyms of Pourtales’s 
name girardii. At the same time lie gives a very brief and hasty description of a 
species of synapta from the New England coast which he calls Leptosynapta roseola. 
Thii'teen years later Lampert (’85) gives gracilis Sel. the rank of a good species, but 
places tennis Ayres, girardii Pourt., and ayresii Sel. as synonyms under 8 . inhcerens 
(O. F. MiilL). He ignores Yerrill’s roseola altogether, not even giving it the place of a 
synonym, though in his literature list he gives Yerrill’s paper (1874) as containing the 
description of one new synapta. The following year Theel (’86) placed the names tenuis 
and girardii in the list of synonyms of inhcerens. He says of Selenka’s gracilis that it 
“seems very doubtful; doubtless identical with inhcerens ,” and of Yerrill’s roseola , 
“doubtless not a distinct species.” The very best authority on the group, Ludwig 
(’92), gives gracilis Sel. and roseola Ver. as good species, but ignores tenuis Ayres, 
girardii Pourt., and ayresii Sel., apparently regarding them as synonyms of inhcerens. 
American zoologists have generally followed Yerrill in recognizing two American 
species of synapta, both distinct from the European species, and the names Leptosynapta 
girardii and Leptosynapta roseola have been in common use in this country. European 
zoologists, on the other hand, have generally credited us with but a single species, and 
that one identical with the common European form, inhcerens. A careful comparison 
of numerous specimens convinces me that truth lies between these two positions. 
American zoologists are right in supposing we have two species, but European writers 
are correct in considering girardii identical with inhcerens. The identity of the two 
forms seems to me to be beyond question, for there are absolutely no constant differences 
in either the gross or microscopic anatomy. A comparison of anchors and plates, both 
in size and shape, shows that while the individual differences may be great, they are 
entirely inconstant, and I could not find a single point by which the specimens from 
Naples could be distinguished from those collected at Woods Hole. 
