Decembee 25, 1896.] 



SCIENCE. 



961 



whose form an approach is made stands in the nor- 

 mal series behind or in front of the segment ivhose 

 variation is being considered. The formation of 

 a cervical rib on the seventh vertebra is thus a 

 backward homceosis, for the seventh vertebra 

 thus makes an approach to the characters of the 

 8th. On the other hand, development of ribs 

 on the 20th vertebra (1st lumbar) is a forward 

 homseosis, for the 20th vertebra then forms 

 itself after the pattern of the normal 19th." 



Curiously enough the main argument is, to 

 avoid confusion. The confusion to be avoided, 

 however, is wholly imported in the word 



* travelling. ' Drop the idea of movement of 

 parts and use the ' terms of direction in their 

 usual sense, and there is no confusion. The 



* confusion worse confounded ' comes in when a 

 backward direction is called a forward one, 

 and vice versa. When the 20th vertebra ' be- 

 comes like ' the normal 19th, the locus of the 

 variation is behind the normal, and the direc- 

 tion should be defined from, rather than to, the 

 normal. The 20th vertebra ' becomes like ' 

 one in front of it, but that does not make the 

 direction of variation forward. 



NEW YORK ACADEMY OF SCIENCES, BIOLOGICAL 

 SECTION, NOVEMBER 9, 1896. 



Members of the Columbia University Expe- 

 dition to Puget Sound made reports on the 

 summer's work. 



Mr. N. E. Harrington gave a short narrative 

 of the expedition, including a description of the 

 equipment of the laboratory, dredging, investi- 

 gation and plankton collection. In addition he 

 made a report on the echinoderms, crustaceans 

 and annelids. Mention was made of the rela- 

 tion of the asymmetry in Scutella excentricus to 

 its habit of burrowing and its vertical position 

 in the sand. Abundant material, both larval 

 and adult, of Entoconcha. This mollusc had 

 been noted by Miller in 1852 and Baur in 1864 

 in Synapta digitata and by Semper in Holothuria 

 edulis. The present material was found in an 

 undetermined species of Holothuria. About 

 forty species each of crustaceans, annelids and 

 echinoderms have been identified. 



Mr. Bradney B. Griffin presented the follow- 

 ing report on the platodes, nemerteans and 

 molluscs. 



The Platodes and Gephyrea are relatively 

 scarce. They are represented solely by two 

 dendrocoels, and one phymosoma respectively. 

 The nemertines occur very abundantly, fully 

 fifteen different species were obtained, most 

 of which appear to be undescribed, though 

 some seem to approach more or less closely the 

 European forms rather than those of the east 

 coast of America. The Enoplan species are 

 the more numerous. The molluscan fauna is 

 very rich and varied, ninety-three species of 

 sixty-nine genera were collected. These in- 

 clude, among others, the large Cryptochiton 

 stelleri, which when alive and expanded 

 measures over 20 cm., besides numerous 

 smaller species of Mopalia, Katherina, Toni- 

 cella, etc., that occur in vast numbers on 

 rocks and piles between tides. The nudi- 

 branchs are notable from their bright colors 

 and large size. One species of Dendronotus at- 

 tains a length of over 25 cm. Cases of color 

 variation (Cardium and Acmaea) and color 

 series (Litorina) were to be met with as well as 

 color harmonization ; many chitons and lim- 

 pets are colored so as to more or less resemble 

 the speckled and barnacled rocks upon which 

 they occur. A complete series of Pholadidea 

 penita (the ' boring clam ' ) was obtained which 

 shows the gradual atrophy of the foot and 

 concrescence of the mantle edges as the 

 adult condition is attained. Specimens of Zir- 

 phsea crispata were collected, a related form in 

 which the foot remains functional throughout 

 life. A series of maturation and fertilization 

 stages of this form was obtained. Lepton is 

 not uncommon, a lamellibranch that lives 

 commensal, attached by its byssus to the ab- 

 domen of the crustacean Gebia, and has caused 

 the trophy of the first pair of abdominal ap- 

 pendages of its host. It has developed a 

 median furrow on each valve in adaptation to 

 the body form of Gebia. An interesting case 

 was observed in which an otherwise nearly 

 smooth Placuanomia shell had assumed during 

 its growth the concentric raised lines of a Saxi- 

 domus valve upon which it was attached. 



The insects are not very abundant ; they are 

 represented in the collection mainly by a few 

 wood beetles, myriopods (Julus, Polydesmus), 

 and a species of Termes. 



