396 CLAUSj ON THE 



of antennffi^ which in many of the Siphonostouiata are also 

 converted into clasping organs_, is shown beyond doubt by the 

 circumstance that the latter in some instances present two 

 branches, and consequently resemble in some degree the pair 

 of two-branched members which exist in the larval stage of 

 life. But in Lernceopocla Galei (fig. 10), I find that the 

 second pair of antennae are two-branched ; and the same is the 

 case, according to Nordmann's figures, in Tracheliastes poly- 

 colpus and Achtheres percarum, and, according to those of 

 Kollar, in Tracheliastes stellifer and Basanistes Huchonis, 

 being regarded by both authors as pineer-like jaAvs. To this 

 clasping apparatus succeed the proper oral members, consist- 

 ing of the mandibles enclosed in a conical beak, and armed 

 towards the point with a definite number of lateral teeth. 

 As towards the base they expand into a broad surface, they 

 approach in their general form the mandibles of the Cyclopidte, 

 between which and the slender piercing setse of the Sipho- 

 nostomata they constitute a sort of intermediate form (figs. 7, 

 8 c, 9 c). On the sides of the conical beak, which, like that 

 of the Siphonostomata, consists of a flattened labium and a 

 curved labrum, arise the equivalents of the maxillae, the palpi, 

 which also in their form gradually approach those members, 

 and are produced into several setigerous processes (figs. 8 d, 



The anterior jaw-feet in the different species, which are 

 sometimes close to the oral orifice [Anchorella, Lernceopoda, 

 Brachiella) , sometimes inserted as the base of the clasping 

 arms, and at a considerable distance from the mouth 

 {Achtheres, Basanistes, Tracheliastes) , present, in their mor- 

 phological construction, in all respects the characters of a 

 first pair of jaw-feet (fig. 7e). Behind these arise the last 

 pair of limbs of the Lernseopoda, which, like the sacciform 

 thoracic feet in Chondracanthus, are wholly unjointed, and are 

 fused together, either throughout their entire length or at 

 the point, into a common organ of attachment. 



These arm-like members, to which the family of the Lernse- 

 opoda owes its appellation, correspond homologically with 

 the jaw-feet of the second pair. The same transformation of 

 the segmental appendages into unjointed processes extends 

 even to those of the head. That this is the correct explana- 

 tion of them is already rendered probable, by that of the 

 members above noticed ; but it is fully confirmed by the 

 structure of the dwarf male, and of the Nauplius-\ike larva. 

 The male Lern^eopods, with which I am acquainted, belonging 

 to several species {L. Galli, Anchorella uncinata, Brachiella 

 Triylce), from my own researches, do not difier very far in the 



