PACKAED.] ANATOMY OF NEBALIA. 433 



its fossil allies (see Bibliography), and gave a description of the order 

 and mentioned the types composing it. 



Nearly a year later, in 1880, Glaus, in the last edition of his Zoology, 

 according to Carus' Yahresbericht, 1880, also suggested that Nebalia 

 represented a distinct order, which he calls Leptostraca. We have not 

 seen the last (fourth) edition of Glaus' Zoology (1882), in which the or- 

 der is noticed. 



Habits. — The species of ]N"ebalia inhabit the sea at moderate depths. 

 We have dredged JV. hipes on the coast of Labrador in from four to 

 eight fathoms, and on the coast of Puget Sound we collected a sim- 

 ilar species, just below low-water mark, among fucoids. The fol- 

 lowing is taken from Baird's British Eutomostraca: ''Otho Fabricius 

 tells us that it carries its eggs under the thorax during t\iQ whole 

 winter; that they hegin to hatch in the month of April, and that the 

 young are horn in May. They are very lively, he adds, and adhere to the 

 mother, who appears then to behalf dead. The adult swims in a prone 

 state, using its hinder feet to propel it through the water. They are 

 not very active. Montagu informs us that when moving in the water 

 the superior antennae are in constant motion as well as the abdominal 

 feet, but that the inferior antennse are usually motionless and brought 

 under the body. They are found, according to Leach, on the south- 

 western and western coasts of England, under stones that lie in the mud, 

 amongst the hollows of the rocks; and Mr. McAndrew dredged it from 

 a considerable depth amongst the Shetland Isles." 



1. — The anatomy and development of l^fEBALlA. 



The first published description of the present species was by Kroyer, 

 in his Naturhistorisk Tidskrift (Ser. 2, Bd. 2). It is written in Danish, 

 and not accompanied by any figures. 



In Nebalia hipes the body is rather slender and somewhat compressed, 

 the anterior half protected by a carapace, beyond the lower edge of 

 which the broad thin phyllopodiform feet do not project. 



The carapace. — The head and anterior half of the body, including the 

 thorax and four anterior abdominal segments, are covered by the cara- 

 pace, which on the lower edge extends below the ends of the thoracic 

 feet, covers the basal joints of the antennge, and entirely covers the 

 mouth parts. The sides are compressed, and are drawn together over 

 the body by a large but rather weak adductor muscle (PI. XXXVII, 

 fig. 6), situated a little in front of the middle of the thorax. There is no 

 large highly specialized adductor muscle connecting the two sides of the 

 carai)ace, nor any well-marked round muscular impression in the cara- 

 pace, such as is characteristic in the Estheriada; ; nor is there any hinge, 

 a still more characteristic feature in the bivalved Phyllopods. On the 

 contrary, as seen in PI. XXXVI, fig. 3, representing the carapace re- 

 moved from the body and flattened out, there are no signs of a median 

 hinge-joint. 



The nature of the rostrum is one of the diagnostic features of this 

 order. In Nehalia, the rostrum is long and narrow, oval, seen from 

 above, terminating in an obtuse point quite far in advance of the head. 

 It is loosely attached to the sinus in the front of the carapace, and thus 

 forms a long, narrow, tongue-like flap, with a free movement up and 

 down. It is thus seen to be rather a movable appendage of the cara- 

 pace than a solid, immovable continuation of it, as in the Decapoda. 

 Upon removing the carapace and flattening it out, it is seen to be 

 readily comparable with the carapace of Ceratiocaris. 

 28 H 



