116 
MR, W. K. BROOKS OK LUCIFER : 
Development of Lepas fascimlaris and the ‘Archizcea ’ of Cirripedia,” by Pi. von 
Willemoes-Suhm, Ph.D., Proc. Boy. Soc., Dec. 9, 1875, pp. 129-130) to be the 
Nauplius of a Barnacle, in all probability Lepas australis. 
Claus, on the other hand, believes that the Zoea has no such ancestral significance 
(“ Untersuchungen,” &c., p. 31). That it has been formed by secondary modification 
of the Protozoea, and that the views of Muller and others, that the Zoea presents a 
picture of the remote ancestor of the Malacostraca, is fundamentally erroneous; and 
not only this, but that the Protozoea itself is the result of the extreme secondary 
modification of an ancestral form which Claus proposes to call an Urophyllopod, and 
which he believes to have had the following characteristics (“ Untersuchungen,” p. 23): 
A greatly developed shield-like carapace, produced by a fold of the integument in the 
region of the maxillae, and probably armed with median and unpaired spines; two 
maxillary segments and appendages, eight somites of the mid-body with appendages, 
and six abdominal somites with swimmerets and telson; a many-chambered heart; 
compound eyes, probably stalked; a first antenna with sensory hairs; locomotor 
second antennae, in which the exopodite was probably a scale; the mandible probably 
lacked a palpus ; the metastoma was represented by a pair of paragnathi; the maxillae 
had their basal joints modified for mastication, their endopodites reduced to a jointed 
palp, and the exopodite modified to form a scoop or scaphognathite for regulating the 
flow of the respiratory current under the carapace. 
The following eight pairs of appendages were more like Schizopod feet, and each of 
them carried a basal gill-plate ; the six pairs of abdominal appendages had large basal 
joints with two branches and gill-plates. 
Claus believes that we may recognise in Nebalia, which has stalked eyes, a scale 
on the first antenna; only one long flagellum on the second antenna ; a mandibular 
palp; a highly specialised, long jointed endopodite on the first maxilla ; two long 
limb-like rami on the second maxilla ; eight pairs of phyllopod-like thoracic limbs with 
jointed endopodite, flat, spiny exopodite and gill ; six pairs of pleopods, the last two 
rudimentary ; and a seventh somite between the sixth abdominal somite and the 
deeply-forked telson (“ Ueber den Bau und die Systematische Stellung von Nebalia,” 
Zeit. f. Wiss. Zool., xxii. p. 323-330), a very slight modification of this ancestral 
Urophyllopod. 
He gives on pages 69—71 of his “ Untersuchungen/'’ &c., a long, minute, and 
extremely ingenious explanation of the way in which this Urophyllopod stage of 
development became converted by secondary modification into the Malacostracan 
Protozoea, and afterwards, by still greater modification in the same direction, into 
the typical Zoea of the higher Decapods. 
The facts which have been detailed and tabulated with reference to the metamor¬ 
phosis of the Sergestidse and Pencets seem to substantiate at least a portion of this 
view, and to show that the typical Zoea is a secondary modification of the Protozoea; 
