128 NEW YORK STATE MUSEUM 



The Malacostraca are divided into six orders, of which all but 

 the first are represented in New York city : I Phyllocarida, 2 Schizo- 

 poda, 3 Decapoda, 4 Stomatopoda, 5 Cumacea, 6 Arthrostraca. 



Order I FHYLLOCARIDA 



Small Malacostraca which have some of the characters of the 

 Entomostraca and form a connecting link between them and the 

 Malacostraca. Head and thorax with malacostracan number of seg- 

 ments, with a bivalved carapace, and with feet leaflike. Abdomen 

 with eight segments, with biramous appendages and a pair of caudal 

 stylets. 



The principal genus is Nebalia, and a species of this, N . b i p e s 

 Fab., is common in the North Atlantic but has not been taken as 

 far south as New York. 



Order 2 SCHIZOFODA 



Malacostraca in which the thoracic appendages are all biramous, 

 and the anterior ones are only to a slight extent modified as maxilli- 

 peds. A thin, soft carapace is present but does not cover the pos- 

 terior segments. Eyes stalked. 



A small group of forms which are known as opossum shrimps, 

 three species of which are found in New York city waters. 



Mysis stenolepis Smith 



My sis stenolepis Smith. In Verrill. /. c. 1874. p. 551. 



Body more or less cylindric. Carapace produced into a short, 

 blunt rostrum : inferior angle with a sharp tooth. Antennal scale 

 rather longer than carapace, ciliated ; flagellum of antennae as long 

 as body. Abdomen somewhat geniculated between first and second 

 segments. Inner lamellae of the sixth segment slightly longer than 

 telson. 



Length : male 23 mm, female 30 mm. Color white, marked with 

 black pigment spots, somewhat stellate in form. 



Very common in the eelgrass in Great South bay. 



Two other species of Schizopoda will probably be found, both 

 smaller than the preceding. Mysis americana Smith, meas- 

 ures 10-12 mm and the antennal scale is but three quarters the length 

 of the carapace. The inner lamella of the sixth abdominal segment 

 is as long as the telson. Found among eelgrass. 



