373 Bihtiographicat Notices, 



warrant the establishment of a new genus (^wcAia?ws,Kr.), distinguish- 

 able from Mysis principally by the shape of the dorsal shield and by 

 the second pair of foot-jaws terminating in organs of prehension 

 formed by the last three joints : the only species is called typicus. 

 Then follow the descriptions of Promysis Galatece, Kr., from the In- 

 dian Sea, and of Dymas typusy Kr., a new genus belonging to Dana's 

 subfamily Sceletince, and forming an intermediary link between 

 Mysis and Myto. My to Gaimardi, Kr., was also discovered during 

 the voyage of * La Recherche,' and described in the second series of 

 the * Tidsskrift,' vol. i. pp. 470-4/6 ; a figure and analyses are found 

 in the * Voyages,' &c., tab. 7. fig. 1 a-y. Dr. Kroyer gives in the 

 present volume (p. 03) a Latin explanation of the said figure. The 

 other new genera and species are illustrated by two plates closely 

 filled with analytical drawings, with a Latin explanation, a table of 

 measurements being also appended. A continuation of these carcino- 

 logical contributions may be expected in the following parts of the 

 periodical. 



The history of the larva of Gastrus Fqui has been the subject of 

 several treatises by different authors, of which doubtless the most 

 remarkable is one by Schroeder van der Kolk, the celebrated Dutch 

 anatomist. The investigations on which this treatise was founded 

 were partly undertaken before 1830, when some of the drawings 

 were exhibited at a meeting of naturalists in Heidelberg ; but the 

 paper was not pubhshed till 1845. It was written in French, and 

 appears in the eleventh volume of the * Nieuwe Verhandelingen der 

 eerste Klasse van het koninklijk-nederlandsche Institut.' Never- 

 theless this remarkable paper seems to be very little known ; and in 

 the most current handbooks there is no mention of it, not even in 

 the author's countryman Van der Hoeven's well-known * Manual of 

 Zoology.' This oblivion is highly undeserved ; and the only circum- 

 stance that perhaps in some degree may explain it is that, along with 

 his excellent account of the anatomy of the said larva, Schroeder van 

 der Kolk proposes certain theories concerning the use of the organs 

 he so ably describes which could not but seem suspicious to his con- 

 temporaries, and which also in part have turned out to be fallacious. 

 The volume of the Danish * Tidsskrift ' which we are reviewing con- 

 tains, in a paper by Mr. Meinert, several valuable contributions to 

 our knowledge of this interesting animal, in the shape of a criticism 

 of Schroeder van der Kolk's statements as to the organs of respira- 

 tion, digestion, and circulation. 



The respiratory system consists, as is generally the case with the 

 larvae of dipterous insects, of a cavity near the posterior end of the 

 animal, from which several tracheae issue, two being larger than the 

 others, and reaching (one on either side) to the vicinity of the head. 

 In the larva of Gaslrus Equi the anterior ends of these^ two long 

 tracheae are horny, and show a great number of perforations. They 

 are attached to the inner extremity of two short tubes, which corre- 

 spond to openings in the skin, and through which the tracheae may 

 be either brought to a level with the general surface of the body or 

 drawn back, and thus protected from injury, Schroeder van der 



