260 BRITISH ENTOMOSTRACA. • 



Of late years, much more has been done by the con- 

 tinental zoologists to extend our knowledge of these 

 curious little creatures. Otto, in the ' Nova Acta Natur. 

 Curios.,' 1828, Burmeister, in the same work for 1831, 

 Kroyer, in his ' Tidsskrift,' 1838-9, and M. P]dwards, in 

 the ' Ann. des Scien. Nat.,' 1833, and in his ' Hist. Nat. 

 des Crust.,' 1840, have given us a great deal of extremely 

 interesting information with regard to their habits, ex- 

 tended our knowledge as to the number of species, and 

 brought forward a variety of startling facts respecting the 

 young, and the curious changes of form they undergo in 

 their advance to maturity. In America, Pickering and 

 Dana have studied carefully a species found abundantly on 

 the common cod-fish of their coast ; and in a lengthened 

 memoir in the ' American Journal of Science' for 1838, 

 have given a most minute description of it, with abundant 

 anatomical details. They do not appear to have followed 

 up the hatching of the young animals ; but Mr. H. 

 Goodsir, in a paper in the 'Edin. Philos. Journal' for 1842, 

 has contributed somewhat to our knowledge concerning 

 the young of the common species found in Scotland. 



Anatomy and Physiology^ Sj'c. — The Caligi are generally 

 of a more or less oval shape, and depressed. The body 

 of the animal consists of two principal portions. The 

 anterior, frequently much the larger, consists of an oval, 

 shield-shaped carapace or buckler, which includes the 

 head and greater portion of the thorax. The posterior, 

 sometimes not a fourth part the size of the other, com- 

 prises the remainder of the thorax and abdomen. 



The anterior or cephalo-thoracic portion is formed of a 

 flexible coriaceous substance, usually transparent, and 

 composed, according to Pickering and Dana, of two coats. 

 On its fore part, which is obtusely rounded, we perceive a 

 narrow plate, notched in the centre, and its posterior por- 

 tion has generally a deep sinus on each margin. The 

 dorsal surface is marked by several lines or furrows, which 

 divide it into four distinct portions. These furrows are 



