PLATE III. 
Development of Crrriepisa. Figures from’ Fritz Méuter, W. Linisesorc, Cuartes Darwin, 
P. P. C. Hoek, Cart Ciaus, ALEXANDER AGassiz, and C. Spence Bate. 
1. Dorsal spine. ov. Ovary. 
2. Ventral spine. pe. Polar cell. 
a. Fold of blastoderm. ph. Posterior horn. 
ab. Abdomen. pp. Protoplasm. 
6. Fold of blastoderm. s. Spermatozoa ? 
6l. Blastoderm. t. Testis. 
cp. Carapace. vt. Yolk. 
et. Embryonic cuticle. a. Orifice of brood-cavity. 
d. Suctorial disk. B  Chitinous shield. 
dp. Deutoplasm. y. Crown. 
J- Frontal sense-thread. 6. Chitinous plate. 
Sh. Frontal horn. e. Rootlike organs. 
gl. Gland at base of frontal horn. ¢. Cleavage sphere. 
i. Intestine. é Tail. 
lb. Labrum. ¢. Anterior part of adult Peltogaster. 
ne. Nucleus. w. Thorax. 
ocl. Ocellus. 
The Roman numerals denote the appendages of the body in their consecutive order. 
1-7. Development of Rhizocephala. 
1-6, from Miiller, Die Rhizocephalen, eine neue Gruppe schmarotzender Kruster. Arch. Naturgesch., XXVIII. 
Taf. I., 1862 ; Die zweite Entwickelungstufe der Wurzelkrebse (Rhizocephala). Ubid., XXIX., Taf. IIL., 
fig. 1, 1863. 
1. Egg from the brood-chamber of Lerneodiscus Porcellane, with four cleavage spheres. Magnified 90 diameters. 
2. First larval stage, or nauplius, of the same, from below, magnified 180 diameters. cp, margin of carapace, 
76, labrum. oc, ocellus. vé, remains of the yolk. I, II, III, first, second, and third pairs of swimming- 
feet. There is no mouth at this stage. A pair of frontal sensory threads is present, although not repre- 
sented in the figure. 
8. Second or pupa stage in the development of the same. The dark oval body is the nauplius eye, now of 
extraordinary dimensions. Paired eyes are not present. The carapace has become folded together so as to 
enclose the body. The second and third pairs of appendages of the nauplius have been discarded, the first 
pair have become prehensile, adapted for the attachment of the larva, and six pairs of swimming-feet 
(VI-X1) are present on the thorax. &, posterior or abdominal part of the body, ending in a pair of two- 
jointed processes, each bearing two terminal sete. The pupa attaches itself by the prehensile antenne to 
the abdomen of its host, throwing out rootlike filaments which entwine about its intestine or ramify through 
its liver, drawing nourishment therefrom. The remaining appendages are cast off. 
4, Adult, attached to the ventral side of the abdomen of a Porcellana. Slightly magnified. 
5. A smaller specimen removed from its host, viewed from the ventral side, magnified 15 diameters. 02, ovary, 
t, testis. a, orifice of the brood-chamber. 8, chitinous shield. y, crown. 
6. The portion of the adult Lernwodiscus which lies within the Porcellana, magnified 25 diameters. 7, intestine 
of the Porcellana. ‘y, crown. 64, chitinous plate. ¢, rootlike processes growing about the intestine of the 
Porcellana. 
- Exuvie of Peltogaster sulcatus, pupa stage, fixed by the prehensile antenne (I) in the opening of the mantle 
of the adult, magnified 200 times. ¢, anterior end of adult Peltogaster. From Lilljeborg, Supplément au 
Memoire sur les Genres Liriope et Peltogaster H. Rathke. Nova Acta Reg. Soc. Scient. Upsal. [3.] IIL., 
Pl. VIII. fig. 34, 1860. 
8-12. Development of Cryptophialus minutus, from Darwin, A Monograph on the Subclass Cirripedia. Balanide, 
Pl. XXIV., London, 1854. 
8. Oval embryo. 35 times the natural size. 
9. Later stage. Two horns (1) are developed at the anterior part of the body, and one, representing the abdo- 
men (a 4), at the posterior end. On same scale as the last figure. 
10. Later stage. The posterior horn has shrunk. The two anterior horns have approached each other on the 
future ventral surface and contain within them the prehensile antenne of the later stage. At this stage the 
larve adhere by the tips of the anterior horns to the inner tunic of the sac of the parent. On same scale 
as the last figure. 
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