494 



SCIENCE. 



LN. S. Vol. I. No. 18. 



of the Brachiopoda the author speaks of 

 the bivalved shell, 'similar to that of a 

 bivalve moUusk,' but he does not add that 

 the shells are dorsal and ventral, a point 

 in which they differ from any moUusk. On 

 p. 271 it is stated that eyes do not occur in 

 these animals, meaning, of course, the 

 adults, though on the next page the young 

 Argiope is credited with eye-spots ; the fact, 

 however, that they occur in the larva of The- 

 cidium not being nientioned. In the bibliog- 

 raphy the papers of Morse on the develop- 

 ment of Terebratulina and of Kowalevsky 

 on Argiope, Thecidium, etc., are omitted, al- 

 though the lower half of the page is left 

 blank, and there was abundant room for 

 the titles. 



The treatment of the moUusca is in some 

 respects unsatisfactory, though the anatom- 

 ical details appear to be correctly and care- 

 fully stated. We should decidedly differ 

 from the view that Lamellibranchs, or Pely- 

 cj^oda, as it is now the fashion to call them, 

 though the name is not nearly so apt or gen- 

 erally applicable as the older term, are in- 

 termediate between the Gastropoda and 

 Ceptalopoda. They have no head, and it 

 seems much more natural to suppose that 

 they have more or less directly descended 

 from the Amphineura. The position as- 

 signed them by Gegenbaur, next above the 

 last named group and below the Cepha- 

 lophora, seems to us to be a more natural 

 one. And speaking of the last named 

 group, it is a pity that there should not be 

 more figures of these obscure generalized 

 forms, especially of the ladder-like nervous 

 system of the different genera to show their 

 relationship to Chiton, though the discus- 

 sion of their affinities is excellent. In 

 speaking of the Gastropods the use of the 

 clumsy German term ' visceral hump ' seems 

 objectionable ; we should prefer to call it 

 the visceral mass. The visceral ' hump ' in 

 a Cephalopod is in reality all of the body 

 behind the head. 



The definitions or diagnoses of the sub- 

 divisions of the ' types ' placed at the end 

 of each chapter are too brief or defective 

 and not always, it seems to us, happily 

 worded. In those of the Gastropoda and 

 Cephalopoda, the fact that they have a well 

 differentiated head is not mentioned, though 

 the ' visceral hump,' if the student clearly 

 understands what that is, is said to be well 

 developed. 



The same lack of completeness applies to 

 the diagnoses of the Crustacea, and particu- 

 larly to those of the insects, while those of 

 the Arachnida are much better. 



The Tracheata (myriopods and taseets), 

 as in some other recent works, are not 

 treated with such detail and thoroughness, 

 nor in the case of the present book, so care- 

 fully and accurately as the Crustacea. It 

 appears to be wholly a compilation, and 

 not the result of autoptic study. This is not 

 the case in Siebold's excellent Anatomy of 

 the Invertebrates, which, though published 

 forty years ago, is still for Tracheata useful 

 and reliable. Our author's account of the 

 anatomy of insects is somewhat faulty and 

 needs revision in numerous places. 



The spiral band of the trachea is said to 

 extend along the tube, whereas it is not con- 

 tinuous, but varies much in length and 

 makes fi.-om one to four or five turns, a 

 single tracheal branch thus having many 

 such disconnected spiral bands. 



The olfactory organs of the antennse are 

 not setse alone, but the pits to which the 

 auther does not refer are far more numer- 

 ous. The elements of the ovipositor are not 

 situated on the ' last abdominal segment' 

 (p. 414), while the cerci (p. 489) are not 

 regarded by the author afe equivalents of 

 the jointed appendages, though they are 

 obviously so, whatever maj' be said of the 

 parts of the ovipositor. It is also a ques- 

 tion whether the ' spring ' of Collembola is- 

 not the homologue of the legs. 



It is rather venturesome to saj^ that in 



